Time-Resolved Spectroscopy of Bulk and Thin Film Structure and Dynamics

9317198纳尔逊飞秒到毫秒时间分辨光谱的凝聚态物质将被用来理解固体和液体结构变化的动力学。本课程将研究玻璃形成液体和聚合物中晶相之间的结构相变和结构演变。结果将根据结构变化的理论模型和分子模型进行分析，结构变化理论模型描述了整个材料类别的行为，因此超越了个别材料，分子模型试图通过考虑特定材料的不同特征来解释特定材料的行为。还将对薄膜的机械和导热性能进行测量。目标是了解界面的线性机械响应、通过破坏性测试测量的非线性响应(例如剥离)以及界面化学和粘结之间的关系。薄膜聚合物方面的工作将立即产生实际影响。该方法可以非接触、无损、现场快速测定微电子、防护涂层和其他应用中使用的支承或非支承聚合物薄膜的机械和热性能(弹性和损耗模数、热扩散系数)。如果非接触式粘接质量评估被证明是可能的，这将为应用社区提供一个真正革命性的工具。***

9317198 Nelson Femtosecond through millisecond time-resolved spectroscopy of condensed matter will be conducted to understand the dynamics of structural change in solids and liquids. Structural phase transitions between crystalline phases and structural evolution in glass-forming liquids and polymers will be examined. The results will be analyzed in terms of theoretical models of structural change, which describe the behavior of whole classes of materials and which therefore transcend individual materials, and in terms of molecular models which attempt to explain the behavior of specihc materials by taking their distinguishing characteristics into account. Measurements of the mechanical and thermal conductivity properties of thin films will also be performed. The goals will be to understand the relations between the linear mechanical response of the interface, the nonlinear response (e.g. peeling) measured by destructive tests, and the interface chemistry and bonding. The work on thin film polymers will have an immediate practical impact. The proposed method permits noncontact, nondestructive, rapid in situ determination of mechanical and thermal properties (elastic and loss moduli, thermal diffusivities) of supported or unsupported polymer films used in microelectronics, protective coatings, and other applications. If noncontact adhesion quality assessment proves possible, this will present a truly revolutionary tool to the applied community. ***